By poo picking with a cat litter scoop we don't tend to get loads of sand in amongst the daily clean out so it goes in the compost with the rest.
I use Milton to disinfect, I think it comes in all forms! I would think any water soluble disinfectant which is safe for animals would be fine. I get a huge bucket and shovel the sand in, add water and the disinfectant and stir with a big stick. Secure a muslin over the end and tip out the water. I put the sand straight back down and find it dries pretty quick in a weather proof building. I only do this every 6 months